Internal combustion engine



rch 28, 1939.. J. E. FULLER 2,152,037

Y INTERNAL COMBUSTION ENGINE I Filed Nov. 18, 1936 3 Sheets-Sheet l QC?I r 5 M in Q 32 L a;

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March z8,` 1939. E, FULLER 2,152,037

INTERNAL COMBUSTION ENGINE Filed Nov. 18, 1936 m3 Sheets-Sheet 2 rch 28,1939. 1E FULLER 2,152,037

INTERNAL COMBUSTION ENGINEA Patented Mar. 28, 1939 UNITEDV STATES PATENTOFFICE 8 Claims.

This invention relates to engines of the internal combustion type andmore particularly to such engines as receive their fuel by injectionrather than by carburization, and the invention deals especially withthe methods of and apparatus for injecting fuel into the cylinders ofsuch engines.

It is a general object of the present invention to provide novel methodsand apparatus for fuel injection for internal combustion engines.

More particularly, it is an object of the invention to provide a methodof and means for delivering fuel to the combustion chambers of internalcombustion engines by means of the suction of and compression orexplosion pressure of certain cylinders.

An important feature of one embodiment of the invention consists in theprovision of a fuel injector for the combustion chamber of eachcylinder, together with means to associate this injector with a sourceof fuel and the suction and pressure of a previously operating cylinderfor charging the injector with fuel and for discharging the fuel intothe combustion chamber.

An important feature of a second form of the invention consists in theprovision of an exhaust heated chamber for partially vaporized fuel, aninjector for supplying liquid fuel and gas to said chamber and means forassociating said injector with a source of fuel and a source of cylindersuction and pressure for charging the injector and discharging the fuelinto said chamber.

A further feature of this embodiment comprises a discharge jet leadingfrom the exhaust heated chamber to the intake manifold in such a manneras to increase the rate of air flow in the manifold while mixing thecharge therewith.

A further important feature of both embodiments of the invention residesin the combined regulation of the air inlet and-the fuel supply inaccordance with the load demand of the engine.

Another important feature of both embodiments of the invention residesin the structural arrangements and operating methods for the fuelinjectors whereby pressure developed in a cylinder of the engine, whenon compression or explosion, is caused to discharge and atomize the fuelfrom the injector into the cylinder then associated therewith, whichfuel in predetermined quantity is drawn into the injector by the suctionpressure of the first mentioned cylinder.

Other and further featuresand objects of the invention will be moreapparent to those skilled in the art upon a consideration of theaccompanying drawings and following specification wherein are disclosedtwo embodiments of the main invention and two embodiments of the fuelinjector, it being understood, however, that these disclosures are onlyexemplary `and that such changes, combinations, and Variations may be 5'made therein as fall within the scope of the appended claims, withoutdeparting from the spirit of the invention.

In said drawings:

Fig. 1 is a side elevation of the upper portion 10 of the cylinder blockand head of an internal combustion engine fitted with apparatus inaccordance with the first embodiment of the invention;

Fig. 2 is a transverse vertical section taken on line 2--2 of Fig. 1;

Fig. 3 is a section on an enlarged scale taken on line 3-3 of Fig. l andshowing the fuel regulating valve in detail;

Fig. 4 is a sectional View on an enlarged scale of a modified form offuel injector, the view being similar to that of the preferred form ofinjector shown on smaller scale in Fig. 2; and

Fig. 5 is a view similar to Fig. 1, but showing in vertical,longitudinal section the manifolds and fuel injection means of a secondembodiment of the main invention.

Internal combustion engines' may in accordance with one classificationbe divided into two groups, first those in which the fuel is preparedoutside of the cylinders into a vapor by the admixture therewith of allof the air necessary for combustion. Such engines are by far in thelargest proportion and make use of a carburetor or similar device forvaporizing the fuel and 35 mixing it with air. The second group ofengines makes use of fuel injection, where the fuel is delivereddirectly into the cylinders or inlet manifold adjacent the cylinders ina liquid form. Such engines are commonly but improperly known as Dieselengines, this term being properly applied to only certain types of fuelinjection engines where the fuel in liquid form is delivered into thecylinder at the end of the compression stroke and is ignitedspontaneously from the heat of the compression of the air therein.

The present invention falls into the second group but is not of theDiesel type, for in one embodiment the fuel is sprayed into thecylinders during the suction or compression stroke of the pistontherein, and in the other is sprayed into a chamber communicating withthe inlet manifold.

In engines of the Diesel type or so-called solid fuel injection, i. e.,without air, the fuel is supplied under high pressure by the operationof 55 one or more pumps and great difficulty is experienced in supplyingthe exact required quantity of fuel to each cylinder. Because of thehigh pressure against which the fuel must be deliv ered, the pumps andinjectors wear rapidly and are costly to build and repair. In anotherform of engine the fuel is injected by the use of air under highpressure, and since this air must be at a higher pressure than themaximum compression pressure in the cylinder, it is diicult to supplyand requires a costly pump. In accordance with the present invention,fuel is supplied without the use of extraneous pump equipment but thefeeding of fuel to one cylinder is obtained by making use of the nominalchanges in pressure in another cylinder, and thus all separate pumpequipment is done away with and the engine materially simplified. Whenthe fuel is injected on the suction stroke of each cylinder, it is notdelivered against any pressure and light weight, simple parts can beused. Sometimes it is an advantage, however, to inject the fuel duringthe compression stroke which can readily be done with the type of enginenow to be described.

The invention is applicable to engines of any multiple number ofcylinders and to either the two stroke or four stroke cycle type. Forconvenience in illustration the invention is disclosed in connectionwith the four cylinder, four stroke cycle type vertical engine ascommonly used for automotive and industrial purposes.

Referring now to Figs. 1 and 2 for an illustration of the invention,there is shown the engine cylinder block I il having the inset cylindersleeves II providing the water jackets I2 for cooling in the customarymanner. The cylinder head I3 contains the usual water chambers, thecombustion chambers I4, the precornbustion chambers I5 and suitablevalve-in-the-head mechanism of conventional form, the passages from thevalves in each cylinder leading respectively to the exhaust manifold I3and the intake manifold I 'I provided with a suitable intake pipe I8leading from the air filter I9. An air throttle valve 20 is provided inthe pipe I8.

Each precombustion chamber is fitted with a closure plug 2l receivingthe spark plug 22 for ring the charge. The exact form of the combustionchamber and precombustion.- chamber plays no part in the presentinvention. A passage 23 in the wall of each precombustion chamber isthreaded as at 24 to receive the threaded end of an injector 25 kepttight by suitable gaskets. The several injectors are connected bysuitable conduits or manifolds 26 and fittings 21, to a common fuelsupply line 28 through the interposed fuel regulating valve 29 shown indetail in Fig. 3, to be later described. The operating arm 3l) on thisregulating valve is connected by a link 3l to an operating arm 32 on theshaft 33 of the air throttle valve 20 whereby the two can be operated inunison, for instance, by a linkage connected to the arm 34 also on thethrottle valve shaft. Operation of this arm permits simultaneousadjustment of the quantity of fuel and quantity of air admitted to allof the cylinders.

Fuel is delivered to the line 28 from any suitable reservoir by gravityfeed or it can be lifted through a reasonable distance by the operationof the engine as will appear as the description proceeds. The regulatingvalve 2S may be only a needle valve, although it is shown as a morecomplex structure for determining the quantity of fuel to be delivered.From the manifold 26 the fuel flows to each injector through a fitting21 into a check valve assembly 36. This includes a double check, firstthe at valve 31 and second the ball valve 38, the operations of whichare so obvious as to need no description here. Between the checks is themetering passage 39. After passing these two checks in quantitydetermined by the passage 39 and other factors, the fuel enters thepassage 4I) in the body of the injector which leads to the annular fuelchamber 4I associated with the hollow interior 42 of the injector, thetapered end 43 of which leads to the nozzle 44 through which the fuel issprayed into the precombustion chamber I5.

The fuel chamber 4I in the injector is con nected by a passage 46, andits extensions, to a longitudinal bore 41 in the cylinder head. This,plus a companion bore 48, parallel thereto, extend for convenience inmanufacture substantially in full length of the cylinder head and aretapped and plugged at appropriate intervals to produce passages whichconnect the combustion chamber of one cylinder to the annular fuelchamber 4I of the injector of the cylinder next in firing order.

The engine shown has the more or less conventional firing order1--3-4--2 so the passages 41 and 48 are divided into portions best shownin Fig. l where the cylinder numbers are indicated just above the sparkplugs. The passage 41 is divided into the following parts: A, leadingfrom the combustion chamber of cylinder 2 to the fuel chamber of theinjector of cylinder I, which fires just after cylinder 2, and B,leading from the combustion chamber of cylinder 4 to the fuel chamber ofthe injector of cylinder 2. The passage 48 is divided likewise into twoparts, C leading from the combustion chamber of cylinder I to the fuelchamber in the injector of cylinder 3; and D leading from the combustionchamber of cylinder 3 to the fuel chamber of the injector of cylinder 4.In this manner each injector fuel chamber is connected to the combustionchamber of the cylinder prior to it in firing order.

The chamber 42 of each injector is cylindrical and fitted with areciprocable piston 50 closed at the rear and open at the forward end.The closed end includes` a rearwardly extending tubular portion 5Iclosed by and rigidly supporting the valve rod 52 which normally closesthe nozzle 44, in valve chamber 44', as shown in Fig. 1, under theaction of spring 53 extending between the end of the piston and the rearwall of the hollow plug 54 for the chamber in the injector body.

In operation, the engine is cranked for starting purposes with the fueland air control valves partially open, and a limited quantity of air isdrawn in through the intake pipe and intake valve, for instance, tocylinder I creating a suction in its combustion chamber in the wellknownmanner, and this suction is communicated through passage C to the fuelchamber 4I in the injector associated with cylinder 3. This suctionpressure being lower than the fuel pressure, fuel enters through thefuel check valves and the interposed metering passage and the passage`4D tothe annular fuel chamber 4I filling this chamber and possibly partof the bore 42 to an extent dependent on the opening of the fuel valveetc.

As rotation of the engine continues the piston in No. 1 cylinder movesup on compression and this pressure or the still higher pressure ofexplosion is carried through the passage C to the fuel chamber 4I,overcoming the spring 53, driving the piston rearwardly and opening thenozzle 44. The gases coming through the passage C effectively dischargeall of the fuel from the chamber 4| and atomize the same through thenozzle '44 into the precombustion chamber of cylinder No. 3 which is nowon its suction stroke.

The pressure of the gas in passage C is sui-licient to move the pistonrearwardly until it is stopped by abutting the annular end of the cap54. This brings the equalizing port 51 in the wall of the piston back toa position permitting gases within the piston to pass into theequalizing chamber 58 in the cap 54 so that the pressure in this chamberbecomes the same as the pressure on the front of the piston. As thepressure in passage C is reduced, on opening of the exhaust valve in`cylinder No. 1, the gases in the back pressure chamber 58 of cylinderNo. 3 become of higher pressure than those in front of the piston 5!)and the fuel valve closes under the action of these gases and itsspring, leaving the gases trapped in the back pres-sure chamber atsomewhat near the maximum cylinder pressure on compression or explosion.These gases together with the spring maintain the valve closed, untilthe following cycle, against whatever pressuremay develop duringexplo-sion in the cylinder associated with the injector because thisexplosion pressure acts through only the small area of the nozzle 44.

The gases trapped in the back pressure chamber behind the piston of theinjector will eX- pand as the valve closes and after closing a certainamount of radiation loss and slight leakage will reduce the pressurebehind the piston to a lower value of say about 75% of the maximumpressure under the piston when the valve is open. This permits the valveto lift on the following cycle. The percentage of pressure remainingbehind the piston can be adjusted in designing the engine by changingthe Volume behind the piston in relation to the displacement of thepiston and thereby the beginning and duration of the fuel deliveryperiod in relation to the piston position and crank angle can beregulated.

Since the maximum pressure of. combustion usually occurs when the pistonis a few degrees past top dead center, the injector will open about attop dead center of the piston stroke of the cylinder which is operatingit. This times the injection near bottom dead center at the end of theintake stroke of the cylinder being charged. The fuel Valve will startto close a few degrees of rotation after the maximum combustion pressureis' communicated to the underside of its piston. The gas pressure fallsfaster than thegases can ow back through the equalizer port, so with theaid of the spring the valve will begin to close and cut off theequalizer port to hold the gases in the back pressure chamber to tightlyclose the valve. The whole action is very rapid and al1 of the movingparts are light so that quick opening and a quick sharp vcut off areobtained.

As the load and speed of the engine vary each cycle produces anincrement of change of pressure in the equalizing chambers so that theback pressure is maintained in balance with the cylinder combustionpressure. If desired, the valve spring can be `omitted entirely since itis not essential to the operation. The proportioning of the variousparts can be effected to: give a longer or shorter period of injectionas desired.

The injector parts are sub-ject to high temperature and would becomeover-heated except for the continual cooling by the fresh fuel being fedthereto and the partial vaporization of this fuel serving to rapidlylower the temperature. The fuel also acts as a lubricant and seal forthe piston and valve.

The cycle of operations described above in connection with cylinders Iand 3 is repeated for each pair of cylinders in sequential relation sothat the engine operates in the proper ring order and with thepossibility of properly regulating the power to the load. Because of theadequate regulation of both the fuel and air, idling and low speed orpower operation is perfectly feasible.

Although the flow of fuel can be regulated simultaneously with theregulation of the air by the use of a needle valve in the fuel line 28operated'by the link 3i connected to the air valve stem, it is,nevertheless, preferred to use a special form of fuel governing Valve,such as shown in Fig. 3, which is interposed between the fuel line 28and the fuel manifold 26. This valve 29 includes an elongated casting6l) having a central bore 6l closed at one end by a bushing 62 and atthe opposite end by a threaded stem 63 rotatable for adjustment by meansof the arm 30 previously mentioned which is attached to the exteriorportion thereof as shown in the lower portion of Fig. 3, so as to permitsuch adjustment thereon as may be needed. This stem 63 is keptleak-proof by means of a suitable packing gland and nut 64. The bushing62 is longitudinally bored and threaded to receive the stem 66 of theneedle 6T forming a portion ofthe valve. position as shown. The fuelpipe 28 communi- Cates with the bore 6I at the inner end of the stem 63and the fuel manifolds are connected to the extensions 60 drilled tointersect the bore 6| adjacent the inner end of the needle stem 66. Theportion of the bore between the fuel inlet and fuel outlet reciprocallymounts the hollow piston 65, one end of which is provided with theopening 68 cooperating with the needle 61 to regulate the flow of fuel.The opposite end is This stern is adjustable and locked into' closed bya disc 69 perforated at 'ID to permit Y fuel to flow to the inside ofthe piston and having a central opening for the passage of the rod liwhich is secured in the stem 63 and equipped with a head 12 looselyfitting the bore of the piston and perforated at 13 for the passage ofthe fuel to the opening 68. Fitted between the back of the head 12 andthe inner side of the disc 69 is the helical spring 14 adjustable byrotation of the stem 63 so that the normal position of the piston inrespect to the needle can be adjusted in unison with the adjustment ofthe air supplied to the cylinders.

This fuel governing valve regulates the amount of fuel fed to theinjectors according to the air throttle opening and the air pressure inthe cylinders served by the injectors. As the air throttle valve isopened the stem 63 is rotated and the head 12 on the rod 'H compressesthe spring and retracts the piston, opening the needle valve inproportion to the opening of the air valve.

When the engine is running, the pressure differential between the fuelin the chamber behind the piston and that in the fuel manifold 26 tendsto close the valve in accordance with the loading on the spring. Thepressure existing in the fuel manifold 26 is the mean pressure on theintake stroke of all of the cylinders as communicated ious passages tothe annular fuel chambers 4| in the injectors. This provides a balancedcondition between thefuel pressure, the fuel feed through the needlevalve and the spring. On heavy loads the velocity of flow of the fuelthrough the orifices in the piston 6l tends to create a closing actionthereon but because of the wide open position of the air valve requiredduring heavy loads, the control stem 63 will be near its extreme openposition and will supply enough compression to the spring 'I4 tocounteract this closing force. Adjustment of the stem 68 sets the needleinitially to suit idling conditions and the particular fuel being used.The

fuel valve is of particular importance in properly proportioning thefuel to the air in accordance with the demand of the engine.

Under certain conditions, it is simpler and cheaper to inject the fuelinto the intake manifold instead of directly into each cylinder or itsprecombustion chamber, and in Fig. 5 is shown a structure for thatpurpose. Here again the engine is of conventional form and shown as afour cylinder, four stroke cycle type provided with the inlet manifoldl5 leading to a pair of siamesed intake ports 76. The exhaust manifold'l1 delivers the exhaust gases from the four exhaust valves to theexhaust pipe 18, and preferably cast integral with the straight upperportion of the exhaust manifold is the fuel chamber 80.

In the present instance, this chamber is equipped with a pair ofinjectors 8| of the type already described. One is fitted at each end,although it may be possible to use a single injector or in extreme casesseveral, sometimes one for each cylinder. These injectors receive theirfuel from the fuel manifold 82 under the control of the fuel adjustingvalve 83 of the type previously described which receives its fuel fromthe line 84. Suction and pressure for operating the injectors is takenfrom an adjacent cylinder through a pipe B5.

The intake manifold has a lateral neck 88 preferably of Venturi formwhich connects it to a chamber 89 connected to the atmosphere by a tube90 containing the air throttle valve 9| connected to operate in unisonwith the fuel valve 83 by the link 92 as in the preferred embodiment.The chamber 99 is supplied with fuel from the chamber 80 by means of thenozzle 83 axially disposed to the venturi but not extending into it.

In operation the governing valve and injectors operate in the manneralready described and a mixture of fuel and gases from the cylindersupplying the power is discharged from the injector or injectors intothe fuel chamber 80 which is well heated by the exhaust manifold. Thefuel is thus further vaporized in this chamber and remains under somepressure depending upon the compression in the engine, the time theinjector is held open, the sizes of the fuel nozzles and of the jet 93.The fuel-gas mixture discharges from the chamber 80 through the jetnozzle 93 into the throat of the venturi 88 in the air intake to themanifold. The velocity of air flow through this venturi is increased bythe stream of gases expanding into it from the nozzle 93 and thus thedensity of the cylinder charge is increased. The fuel-gas mixture isthoroughly incorporated with the intake air in passing through theventuri and intake pipe. It is found that there will be suicient storageof compressed gas-fuel mixture in the chamber 80 to charge all of thecylinders even though the injectors are operated by but part of them.

If desired the injectors can be attached directly to and inject thefuel-gas mixture into the intake pipe instead of the chamber. Underthese conditions any desired number of injectors may be used, up to oneper cylinder in which case they would be connected for suction andinjection pressures as in the construction of Fig. 1.

In Fig. 4 is shown an alternative form of fuel injector suitable foreither embodiment of the invention, which in its main aspect is similarto that shown in Fig. l. The only difference resides in the piston whichis extended to have a hollow conical end received in the mixing chamber|00 cooperating with the spray nozzle |0| to form the valve. The wallsof the piston are thickened near this end and provided with an exteriorannular recess |02 which always registers with the port |03 connected inthe manner of Fig. 1 to the combustion chamber of the previouslyoperating cylinder. Passages |04 connect this chamber |02 with theinterior of the piston. 'I'he annular fuel chamber |05 has access to theinterior of the piston through ports |06 and the discharge port |07allows the fuel and gas mixture which accumulates in the chamber |05 andin the reduced end of the piston to be driven out into the nozzle IUI.Furthermore, the fuel can be forced along the longitudinal passage |00leading from |05 to |00. In this construction the suction in the passage|03 draws fuel into the reduced end of the piston through the ports |06and then as the valve opens by the movement of the piston discharges itthrough the passage |01 into the atomizing nozzle |0|.

Although the invention has been shown as applied to an engine of thespark ignition type, it is obvious that it can equally as well beapplied to engines of the compression ignition type.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. For use with an internal combustion engine, an injector comprising abody, a nozzle projection on said body, a chamber in said body, a valvefor separating said nozzle and chamber, a piston carrying said valve andmounted for reciprocation in said body chamber, a fuel line connection,a fuel inlet therefrom to the chamber between the valve and piston, acheck valve in said inlet, a fluid passage to the body chamber betweenthe valve and piston for connection to a source of intermittentpressure, and means to normally hold said valve closed.

2. For use with an internal combustion engine, an injector having abody, a nozzle projection on said body. a chamber in said body, a valvefor separating said nozzle and chamber, a piston controlling said valveand mounted for reciprocation in said body chamber, a fuel connection, afuel inlet therefrom to the chamber between the valve and piston, acheck valve in said inlet, means supplying intermittent fluid pressurewaves to the body chamber between the Valve and piston, a chamber behindsaid piston, and a passage between said chambers opened only when therst chamber is open to said nozzle.

3. For use with an internal combustion engine, an injector having abody, a nozzle projection on said body, a chamber in said body, a valvefor said nozzle, a piston carrying said valve and mounted forreciprocation in said body chamber, means for connection to a source offuel, a fuel inlet therefrom to the chamber between the valve andpiston, a check valve in said inlet, a gas passage to the body chamberbetween the valve and piston for connection to a source of intermittentfluid pressure, a chamber behind said piston, a passage between saidchambers opened only when the valve is open to said nozzle and a springin said second chamber acting to hold said valve closed.

4. A fuel injector for operation by intermittent gas pressure wavescomprising in combination, a body having a nozzle and a cylindricalchamber, a seat in said nozzle, a piston operable in said chamber, avalve carried by saidl piston to cooperate with said seat to close o-flsaid nozzle, a spring to normally close said valve, means to supply fuelto the space around the nozzle seat, means tc apply said pressure wavesto said space, and means to equalize the pressure on the two sides ofsaid piston when the valve is opened under increased pressure from oneof said waves.

5. A fuel injector for operation by intermittent gas pressure Wavescomprising in combination, a body having a nozzle and a cylindricalchamber, a seat in said nozzle, a piston operable in said chamber, avalve carried by said piston to cooperate with said seat to close olfsaid nozzle, a spring to normally close said valve, means to supply fuelto the space around the nozzle seat, means to apply said pressure wavesto said space, means to equalize the pressure on the two sides of saidpiston when the valve is opened under increased pressure from one ofsaid waves, and means to maintain the increased pressure on the valveclosing side of the piston when the valve closes and the pressure wavesubsides.

6. A fuel injector for operation by intermittent gas pressure wavescomprising in combination,

a body having a nozzle and a cylindrical chamj ber, a seat in saidnozzle, a piston operable in said chamber, a valve carried by saidpiston to cooperate with said seat to close off said nozzle, a lightspring to normally close said valve, means to supply fuel to the spaceon the piston side of said valve, means to apply said pressure waves tosaid space, means to admit the pressure to the opposite side of saidpiston when the valve is opened, said means isolating the pressurebehind the piston when the valve is closed to assist the spring,

7. A fuel injector for operation by intermittent gas pressure wavescomprising in combination, a body having a nozzle and a cylindricalchamber, a seat in said nozzle, a piston operable in said chamber, avalve carried by said piston to cooperate with said seat to close olfsaid nozzle, a light spring to normally close said valve, means tosupply fuel to the space on the piston side of said valve, means toapply said pressure waves to said space, means to admit the pressure tothe opposite side of said piston when the valve is opened, said meansisolating and slightly reducing the pressure behind the piston when theAvalve is closed whereby the following stroke of the Valve takes placeonly near the maximum of the pressure wave.

8. A fuel injector for use with internal combustion engines and adaptedfor operation by intermittent gas pressure waves comprising incombination, a body having a nozzle bore at one end thereof and acoaxial cylindrical chamber, a hollow piston operable in said chamberand having a valve portion to close said bore, a light spring biasingsaid piston to close said bore, a check valved fuel passage extendingthrough the wall of said chamber, a channel in said piston reg1steringwith said passage and. connected to the interior of the piston near thevalve end thereof, a gas pressure passage through the chamber wall, acorresponding channel in the piston connected tothe interior thereofmore remote from the valve end, a spray opening from the valve end ofthe interior of the piston to adjacent the valve portion, a closedchamber behind said piston, a passage in the piston wall, normallyclosed, said passage cooperating with the chamber wall to connect theinterior of the piston to said closed chamber only when the valve isopen for the purpose described.

JOI-IN E. FULLER.

